A faster CPU noticeably improves a NAS box's file-handling performance. The 2.4GHz Intel Celeron J1800 in QNAP's two-bay TS-251 also facilitates value-added functions, such as on-the-fly video encoding and the ability to run virtual machines. You wouldn't even attempt these tasks on an Atom-powered NAS box. But you need at least 2GB of memory to run the Virtualization Station app that handles virtual machines, and the $499 model that's currently available ships with only 1GB. More on that and similar issues later.
Considering its price--which is cheap for QNAP, but expensive compared to everything apart from Synology's boxes--I wasn't shocked that the company penny-pinched on the TS-251's enclosure. The satin silver and white plastic shell looks cheap, and there are no locks on the drive trays. Fortunately, the cost-cutting stopped there (not counting the 1GB of memory, that is). You get dual gigabit ethernet ports, an HDMI port that can drive a local display, two USB 2.0 ports, and two USB 3.0 ports. The front USB 3.0 port is used for for quickly copying the contents of USB storage devices onto the box.
The eval unit QNAP sent (which came upgraded to 4GB of memory) proved an excellent performer, writing our 10GB mix of files and folders at 53MBps and reading them at 33.5MBps. It wrote a single large 10GB file at over 105MBps. But while speed is a good thing, there are fast boxes available for a whole lot less. QNAP products distinguish themselves with an operating system and software feature set that are nothing short of phenomenal. The HTML interface is a full windowed GUI in a browser. If you haven't seen it, you should check out the live demo at QNAP's site, here.
Of course there are all the usual network and access protocols (FTP, Telnet, SSH, etc.), multiple users, shares, quotas, etc. found in every NAS box. But there are also a host of server and centralized utility functions such as Web and mail serving, content management, video surveillance, BitTorrent (and other) downloading, XBMC multimedia playback to an attached display, DLNA and iTunes streaming, and backup to the cloud.
There's more, much more, but the two most recent additions to the mix are those mentioned up top: on-the-fly and offline video transcoding and the ability to run VMs. Transcoding, which is still in beta, is pretty straightforward, although I didn't have a lot of success with the real-time version or the mobile apps.
Basically, you load the files onto the TS-251, make sure that media serving and transcoding are enabled, then use QNAP's Qfile app (available for Android, iOS, and Windows Phone) to play back the files on your portable device. PCs and Macs have their own codecs and don't require transcoding. Sadly, the Windows Phone app didn't work at all, and the Android app doesn't provide native playback.
In practice, I could only stream real-time-transcoded files to mobile devices at lower resolutions--480p or lower--and not always successfully. On the other hand, straight DLNA streaming worked perfectly (thanks to a wide selection of very competent players on all platforms), and offline transcoding to MP4 worked great. If you deal with a lot of video, it's quite nice to offload re-encoding tasks to your NAS box. You can have the module spit out 240p, 320p, 480p, 720p, or 1080p versions of your files (or any combination thereof). After you get a feel for the maximum you can stream successfully, you can go with that resolution. The TS-251 also supports Plex and AirPlay.
Running a VM worked a whole lot better than the on-the-fly encoding. QNAP's Virtualization Station is very similar to using VMWare or VirtualBox, except that you're using it remotely via a Web browser Most of my VMs are in VirtualBox format, and Virtualization Station supports only OVA/OVF (open virtual format) and QVM, so I created a Windows 7 VM from scratch.
In my tests, the Windows 7 VM operated just fine using both the HTML5 and Java consoles, albeit not nearly as quickly as it would on a local PC. Still, having the ability to access a VM from anywhere on the planet (assuming you've enabled remote access to the TS-251) and know that any data you save with it will be safe at home on your trusty NAS box is quite cool. The TS-251 uses considerably less power than most PCs.
As noted above, the $499 TS-251 ships with only 1GB of system memory, which is not enough to run Virtualization Station. Upgrading requires removing the shell (hint: remove the drives first) as well as the drive cage, so upgrades aren't for the technophobic. A better suggestion is to wait for the $559, 4GB version, which is coming soon.
Camera licenses are another QNAP gotcha: Surveillance Station comes with two, but Surveillance Station Pro includes only one. You can't set up a large-scale camera system with either without purchasing more licenses at $55 a pop. To be fair, QNAP is hardly alone in this practice: Synology and EMC/Iomega play the same game. Still, it pays to peruse the fine print when you spot a QNAP feature you must have.
The TS-251 is a fast, capable NAS box. It's expensive--and you'll need to add memory to take full advantage of its capabilities--but considering you can host your website and email, control video cameras, stream multimedia, and perform a passel of other tasks beyond serving files, it's a bargain for anyone who can exploit its capabilities.
This is not the box to buy if you're just looking for basic network storage and streaming--there are plenty of less-expensive alternatives.